Pot bearings of the foregoing type are known and in use especially for applications in structural engineering. They permit—making them superior to diverse other conventional bearings—in a particularly compact structure, bracing of a supported component on a load-bearing component, in a manner suitable for transmission of large loads, in the case of varying—within certain limits—inclinations of the two components relative to one another, especially due to tilting (“rotation”) of the cover relative to the pot. A pertinent document for structural engineering applications of pot bearings is DIN “Bearings in Construction—Part 5: Pot bearings”, i.e. DIN EN 1337-5, the contents of which are incorporated by reference herein. The patent literature, for example DE 2725621 C2, also relates to the design of pot bearings.
To permit the cover to become inclined relative to the pot (i.e. to tilt or “rotate” around a generally horizontal axis), it is imperative to provide a circumferential annular gap between the cover and the pot. Precisely in pot bearings subjected to particularly high stress, sealing of the elastomer cushion relative to the pot underneath the cover takes on particular importance to ensure that the elastomer cushion does not flow through that annular gap or be pressed out of the associated cavity. According to the pertinent standard (DIN EN 1337-5), brass, polyoxymethylene (POM), carbon-filled PTFE and stainless steel can be considered as material for the inner seal in question. In the case of use of POM, the standard specifies providing a POM sealing chain consisting of individual elements engaging in one another, wherein the POM to be used has a density (according to ISO 1183, incorporated by reference herein) of 1410 kg/m3±20 kg/m3, a melt flow index MFI 190/2.16 (according to EN ISO 1133, incorporated by reference herein) of (corrected!) 10 g/10 min±2 g/10 min, a tensile strength (according to EN ISO 527-2, incorporated by reference herein) of >=62 N/mm2 and an elongation at break (according to EN ISO 527-2, incorporated by reference herein) of >=30%. Furthermore, the production of the inner seal in question from UHMWPE (see WO 2006/042571 A1) has been proposed as an alternative.
The object of the present invention is to provide a pot bearing of the type mentioned in the introduction that is characterized by a performance further improved compared with the bearings with POM inner seal according to the standard.